MONTREAL (UPI) -- Canadian scientists say a new multiple sclerosis drug undergoing trials appears to be safe and effective.

Researchers at the Montreal Neurological Institute said their ongoing investigation is also providing deeper insight into the biology of the complex neurological disease.

The Phase I and Phase II studies involve people suffering relapsing-remitting MS. Treatment with the drug rituximab significantly reduced the number of new brain lesions and the frequency of relapses, times when symptoms of MS flare up.

Rituximab is a therapeutic antibody that selectively targets and depletes a set of immune cells called B-cells by binding to a specific protein on their surface.

"This is the first drug to selectively target B-cells in MS and the significance of its effectiveness is two-fold," said Dr. Amit Bar-Or, a neurologist at the Montreal Neurological Institute at McGill University and lead investigator in the Phase I study. "Not only might it present a significantly improved therapy for patients with relapsing-remitting MS, but it provides a clearer picture of the role that B-cells play in the disease."

The research was presented this week in Boston during the 59th annual meeting of the American Academy of Neurology.